Incidence and risk factors of retinopathy of prematurity

Background Retinopathy of prematurity (ROP) is one of the main causes of visual impairment in premature infants.Objective To determine the incidence and risk factors for ROP in premature infants.Methods This retrospective study included premature infants born in Stella Mmaris Women’s and Children’s Hospital and admitted to the neonatal intensive care unit (NICU) and Neonatology Department from November 2009 to May 2012. We included all premature infants with body weight (BW) < 1500 g or gestational age (GA) < 32 weeks, and selected infants with BW 1500 - 2000 g or GA > 32 weeks with unstable clinical courses who had been screened for ROroP. Data was analyzed with Fisher’s exact test and independent t test.Results Of the 48 premature infants in the study, ROroP was detected in 6 (12.5%) of the subjects. Stages of ROP were classified according to the International Classification of of Prematurity. Stage 1 ROP was detected in 1 (2.1%) subject; stage 2 ROP was detected in 3 (6.25%) subjects; and stage 3 ROP was found in 2 (4.2%) subjects. The 2 infants with stage 3 ROroP required surgery. No was detected in infants with GA > 30 weeks or BW > 1250 g. Respiratory distress syndrome (RrDS), sepsis, blood transfusion, and apnea were found to be associated with development of ROP. Duration of oxygen therapy was found to be a significant risk factor for ROP in a comparison of the no ROP group to the ROP group: 14.0 (SD 9.508) days vs. 3.81 (SD 5.218) days, respectively (P<0.05). In addition, the duration of continuous positive airway pressure (CPAP) usage was also a significant risk factor for ROP, with 1.83 (SD 1.329) days in the ROP group vs. 0.76 (SD 1.122) days in the no ROP group (P<0.05).Conclusions The incidence of ROP in the premature infants in our study is 12.5%. Retinopathy of prematurity is associated with lower BbW, lower GA, lower Apgar score at the 5th minute, RrDS,6,7sepsis, apnea, blood transfusion, aminophylline usage, as well as longer duration of oxygen therapy and CPAP usages.